Lithium ion batteries, nickel hydrogen batteries and other secondary batteries have recently become increasing important for use as vehicle-mounted power supplies or power supplies of personal computers and portable terminals. In particular, lithium secondary batteries, which are lightweight and provide high energy density, are expected to be preferably used as vehicle-mounted, high-output power supplies. In a typical configuration of this type of secondary battery, an electrode is provided that has a configuration in which a material capable of reversibly occluding and releasing lithium ions (electrode active material) is retained on an electrically conductive member (electrode current collector). Typical examples of electrode active materials used in negative electrodes (negative electrode active materials) include carbon-based materials such as graphite carbon or amorphous carbon. In addition, typical examples of electrode current collectors used in negative electrodes (negative electrode current collectors) include sheet-like and foil-like members consisting mainly of copper or copper alloy.
In the production of a negative electrode having such a configuration, a typical example of a method for retaining the negative electrode active material on the negative electrode current collector consists of coating a compound material paste, in which a negative electrode active material powder and a binder are dispersed in a suitable medium, onto the negative electrode current collector (such as copper foil) followed by drying by passing through a hot air dryer and the like to form a layer containing the negative electrode active material (negative electrode compound material layer). In this case, the binder in the negative electrode compound material layer fulfills the role of binding the negative electrode active materials as well as binding between the negative electrode compound material layer and the negative electrode current collector. In addition, the binder in the negative electrode compound material layer also fulfills the role of binding the negative electrode compound material layer to the negative electrode current collector. Patent Documents 1 to 3 disclose examples of technical documents relating to this type of electrode production method.    Patent Document 1: Japanese Patent Application Laid-open No. H11-283615    Patent Document 2: Japanese Patent Application Laid-open No. 2003-157847    Patent Document 3: Japanese Patent No. 3553244